Where do you change the database? In SSRS or Skype for Business Wizard?
Do you back up the encryption keys before removing it?
If you have backup, try to recovery the encryption key and change the database to previous one to check if it is fixed.
Meanwhile, in regard of this error message -- The report server was unable to validate the integrity of encrypted data in the database, you could restart the services and try again. Many people discuss this topic here. You could refer to it.
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